X-ray stress evaluation in phase change GeSbTe material and TiW electrodes

Stress generation and relaxation upon Ge2Sb2Te5 (GST) crystallization were studied by X-ray diffraction technique, which allows the stress in either GST or Ti3W7 (TiW) to be evaluated independently within TiW/GST/TiW multilayer film. The GST crystallization results in tensile stress in the GST film and additional compressive stress in the TiW film, due to volume shrinkage of the GST film. Moreover, the tensile stress in the GST film is significantly increased when it is sandwiched between TiW films. Interfacial effect is proposed to attribute the dependence of stress on the capping layer thickness.